// ==UserScript==
// @name         ElementGetter
// @author       cxxjackie
// @version      2.0.0
// @supportURL   https://bbs.tampermonkey.net.cn/thread-2726-1-1.html
// ==/UserScript==

export var elmGetter=function() {
    const win = window.unsafeWindow || document.defaultView || window;
    const doc = win.document;
    const listeners = new WeakMap();
    let mode = 'css';
    let $;
    const elProto = win.Element.prototype;
    const matches = elProto.matches ||
        elProto.matchesSelector ||
        elProto.webkitMatchesSelector || 
        elProto.mozMatchesSelector ||
        elProto.oMatchesSelector;
    const MutationObs = win.MutationObserver ||
        win.WebkitMutationObserver ||
        win.MozMutationObserver;
    function addObserver(target, callback) {
        const observer = new MutationObs(mutations => {
            for (const mutation of mutations) {
                if (mutation.type === 'attributes') {
                    callback(mutation.target);
                    if (observer.canceled) return;
                }
                for (const node of mutation.addedNodes) {
                    if (node instanceof Element) callback(node);
                    if (observer.canceled) return;
                }
            }
        });
        observer.canceled = false;
        observer.observe(target, {childList: true, subtree: true, attributes: true});
        return () => {
            observer.canceled = true;
            observer.disconnect();
        };
    }
    function addFilter(target, filter) {
        let listener = listeners.get(target);
        if (!listener) {
            listener = {
                filters: new Set(),
                remove: addObserver(target, el => listener.filters.forEach(f => f(el)))
            };
            listeners.set(target, listener);
        }
        listener.filters.add(filter);
    }
    function removeFilter(target, filter) {
        const listener = listeners.get(target);
        if (!listener) return;
        listener.filters.delete(filter);
        if (!listener.filters.size) {
            listener.remove();
            listeners.delete(target);
        }
    }
    function query(all, selector, parent, includeParent, curMode) {
        switch (curMode) {
            case 'css':
                const checkParent = includeParent && matches.call(parent, selector);
                if (all) {
                    const queryAll = parent.querySelectorAll(selector);
                    return checkParent ? [parent, ...queryAll] : [...queryAll];
                }
                return checkParent ? parent : parent.querySelector(selector);
            case 'jquery':
                let jNodes = $(includeParent ? parent : []);
                jNodes = jNodes.add([...parent.querySelectorAll('*')]).filter(selector);
                if (all) return $.map(jNodes, el => $(el));
                return jNodes.length ? $(jNodes.get(0)) : null;
            case 'xpath':
                const ownerDoc = parent.ownerDocument || parent;
                selector += '/self::*';
                if (all) {
                    const xPathResult = ownerDoc.evaluate(selector, parent, null, 7, null);
                    const result = [];
                    for (let i = 0; i < xPathResult.snapshotLength; i++) {
                        result.push(xPathResult.snapshotItem(i));
                    }
                    return result;
                }
                return ownerDoc.evaluate(selector, parent, null, 9, null).singleNodeValue;
        }
    }
    function isJquery(jq) {
        return jq && jq.fn && typeof jq.fn.jquery === 'string';
    }
    function getOne(selector, parent, timeout) {
        const curMode = mode;
        return new Promise(resolve => {
            const node = query(false, selector, parent, false, curMode);
            if (node) return resolve(node);
            let timer;
            const filter = el => {
                const node = query(false, selector, el, true, curMode);
                if (node) {
                    removeFilter(parent, filter);
                    timer && clearTimeout(timer);
                    resolve(node);
                }
            };
            addFilter(parent, filter);
            if (timeout > 0) {
                timer = setTimeout(() => {
                    removeFilter(parent, filter);
                    resolve(null);
                }, timeout);
            }
        });
    }
    return {
        get currentSelector() {
            return mode;
        },
        get(selector, ...args) {
            let parent = typeof args[0] !== 'number' && args.shift() || doc;
            if (mode === 'jquery' && parent instanceof $) parent = parent.get(0);
            const timeout = args[0] || 0;
            if (Array.isArray(selector)) {
                return Promise.all(selector.map(s => getOne(s, parent, timeout)));
            }
            return getOne(selector, parent, timeout);
        },
        each(selector, ...args) {
            let parent = typeof args[0] !== 'function' && args.shift() || doc;
            if (mode === 'jquery' && parent instanceof $) parent = parent.get(0);
            const callback = args[0];
            const curMode = mode;
            const refs = new WeakSet();
            for (const node of query(true, selector, parent, false, curMode)) {
                refs.add(curMode === 'jquery' ? node.get(0) : node);
                if (callback(node, false) === false) return;
            }
            const filter = el => {
                for (const node of query(true, selector, el, true, curMode)) {
                    const _el = curMode === 'jquery' ? node.get(0) : node;
                    if (refs.has(_el)) break;
                    refs.add(_el);
                    if (callback(node, true) === false) {
                        return removeFilter(parent, filter);
                    }
                }
            };
            addFilter(parent, filter);
        },
        create(domString, ...args) {
            const returnList = typeof args[0] === 'boolean' && args.shift();
            const parent = args[0];
            const template = doc.createElement('template');
            template.innerHTML = domString;
            const node = template.content.firstElementChild;
            if (!node) return null;
            parent ? parent.appendChild(node) : node.remove();
            if (returnList) {
                const list = {};
                node.querySelectorAll('[id]').forEach(el => list[el.id] = el);
                list[0] = node;
                return list;
            }
            return node;
        },
        selector(desc) {
            switch (true) {
                case isJquery(desc):
                    $ = desc;
                    return mode = 'jquery';
                case !desc || typeof desc.toLowerCase !== 'function':
                    return mode = 'css';
                case desc.toLowerCase() === 'jquery':
                    for (const jq of [window.jQuery, window.$, win.jQuery, win.$]) {
                        if (isJquery(jq)) {
                            $ = jq;
                            break;
                        };
                    }
                    return mode = $ ? 'jquery' : 'css';
                case desc.toLowerCase() === 'xpath':
                    return mode = 'xpath';
                default:
                    return mode = 'css';
            }
        }
    };
}();
